The present invention relates to a heat resistant work shoe, enabling the wearer to tolerate working on hot asphalt and other heated working surfaces.
For work shoes to correctly isolate the user's foot from intense heat of hot asphalt, the work shoe must necessarily capture some of the conducted heat through the sole and out of the work shoe itself.
Prior art work shoes present a disadvantage since the said soles become hot on hot surfaces and they may even be unbearable to wear, especially in the case of working on hot asphalt materials which may reach 350 degrees F., with the consequent inconvenience and even a risk of burn blisters if the work shoes are exposed to hot asphalt for any considerable period of time.
Shoes incorporating simple or safe ventilating features are already known. Nevertheless, all those devices are based on the elimination of built-up body heat and perspiration. In addition, various shoes have built-in air chambers for the additional purpose of providing resilient air cushions within a shoe.
However, for various reasons the manufacture of high heat resistant work shoes is still necessary. Thus, shoes including parts which ventilate body heat air by means of outlet conduits and the like are known.
U.S. Pat. No. 4,438,573 to McBarron, U.S. Pat. No. 4,888,887 to Solow, and U.S. Pat. No. 4,999,932 to Grim describe air cushioned shoes with pumping members. The ventilating features of these shoes are to regulate the air pressure within the air cushioned reservoirs of the shoes.
U.S. Pat. No. 3,284,930 to Baldwin, U.S. Pat. No. 4,654,982 to Lee, and U.S. Pat. No. 4,941,271 to Lakie, describe boots, such as ski boots, with air and moisture ventilation chambers with outlet ventilation ports on the upper part of the boots.
U.S. Pat. No. 4,224,746 to Kim, U.S. Pat. No. 4,417,407 to Fukuoka, U.S. Pat. No. 4,602,441 of El Sakkaf, U.S. Pat. No. 4,760,651 to Pon-Tzu, U.S. Pat. No. 4,813,160 to Kurnetz, U.S. Pat. No. 4,993,173 to Gardiner, U.S. Pat. No. 4,835,883 to Tetrault, U.S. Pat. No. 5,010,661 to Chu and U.S. Pat. No. 5,025,575 to Lakie also disclose shoes or boots with air ventilation chambers wherein cool air is directed into the shoe or boot and warm moist body heat generated air is directed out of the shoe or boot.
U.S. Pat. No. 4,546,555 to Spaderman, U.S. Pat. No. 4,813,159 to Weiss, U.S. Pat. No. 4,813,161 to Lesley, U.S. Pat. No. 4,813,162 to Harris and U.S. Pat. No. 4,888,888 to Ashton disclose several cushioning features for footwear.
With respect to temperature control footwear, U.S. Pat. No. 4,249,319 to Yoshida, U.S. Pat. No. 4,658,515 to Oatman and U.S. Pat. No. 4,777,740 top Akagi describe shoes or boots designed to insulate and retain heat within the shoe or boot during cold environmental conditions.
Specifically, Yoshida '319 employs the introduction of exothermic heat inserts, Oatman '515 uses a chamber with insulated particles and heat reflective foil to reflect heat back to the foot of the wearer, and Akagi '740 uses closely stitched foam layers to retain heat in cold weather conditions.
These prior art patents have various ventilating features for shoes or boots, some with venting outlet ports located on various areas of the footwear, and some with air ventilating tubes or conduits to increase cushioned comfort and to reduce perspiration for the wearer.
However, none of the devices disclosed in these prior art patents utilize a reflective material specifically combined with a venting system to reduce inside intense shoe temperature build-up for the wearer of work shoes in high heat work environments, such as on hot asphalt road work.
The present invention includes a sole structure with a light upper inner sole separated from a heavier, lower inner sole by a heat collecting chamber, wherein the space between two soles includes a squeezable, bendable insert of numerous, preferably cylindrical, resilient supporting bodies to facilitate air circulation therebetween.
According to the preferred embodiment, an additional heat reflective means is constituted by a layer of cork material capable of dissipating some of the heat reflected away from the shoe by the reflective foil.
An advantageous characteristic, according to the invention, is that the thin reflective layer parts of the work shoe have a concavity, wherein they adapt themselves to the curvature of the upper part of the shoe upper in which they are placed.